Improvement in sewing-machines



UNITED STATES PATENT OEEIGE.

GEORGE REHFUSS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO AMERICANBUTTON-HOLE OVERSEAMING AND SEWING-MACHINE COMPANY, OF SAME PLACE.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 154,084, dated August11, 1874; application iled December 2, 1873.

To all whom it may concern:

Be it known that I, GEORGE REHFUSS, of the city and county ofPhiladelphia and State of Pennsylvania, have invented Improvements inSewing-Machines, of which the following is a specification:

The objects of my invention are to prevent accidental alteration of thetension on the needle-thread of a sewing-machine, and to preventaccidental movement of the workv plate without interfering with itsready withdrawal. attain these objects by combining a pawl and ratchetwith the adjusting-nut A of the tension device, and by combining aspring-retaining pin, H, with the slotted and sliding work-plate I, allas shown in the per. spective view, Figure 1, and sectional views, 2 to5, of the accompanying drawing..

The tension device consists of two disks, f and f the disk f beingforced against the'disk f by a spring, g, the pressure of which isregulated by a nut, A, on the screw-rod h, and the latter carries thesaid spring and disks. (See sectional plan view, Fig. 2.) Intensiondevices of this class where jam-nuts are employed, the nut is apt tobecome y, accidentally turned in' working the machine, and to thus alterthe tension--a defect which I overcome by simply forming ratchet-teeth ion one face of the nut, and by adapting a pawl, j, to these teeth, asshown in the detached sections, Figs.

, 2 and 3. This pawl is secured to or forms part of a spiral spring, bywhich it is constantly held against the ratchet-teeth, the outer end ofthe said pawl being fitted to and slidingin a groove, l, in the fixedarm F, by which it is guided and maintained in proper position inrespect to the teeth. In order to permit access to the shuttle, thereare on the base-plate of the machine two sliding workplates, I and J,the former of which is withdrawn by a movement in the direction of thearrow l, and the latter by a movement in the direction of the arrow 2,Fig. l.

As the work is fed in the direction oi' the arrow 3, it can have notendency to disturb the plate J, but frequently pushes back the plateI-an objection which I overcome by recessing the base-plate to receiveaspring-pin, H, which, when the -plate is in its place, projects into theusual end opening or slot q, made to afford a bearing for the finger inwithdrawing the plate, as shown in the sectional views, Figs. 4 and 5.The pin, without interfering with the operation of the machine, andwithout requiring any alteration of the plate, serves as an effectualretainer to prevent the accidental movement of the work-plate, and yetrequires no special manipulation when the latter has to be drawn ont,for the simple insertion of the linger into the slot q in the act ofwithdrawing the saidplate depresses the pin, as shown in Figs. 4 and 5,and on restoring the plate to its original position the pin will recoiland take its place in the slot, as seen, but will not project above theface of the plate to interfere with the fabric operated on by themachine.

I claim- 1. The combination of the nut A, adapted to thescrew-rod h, itsratchet, and the pawl j,

arranged to move with the nut, all as and for the purpose set forth.

2. The combination of the sliding plate I, having the usual slot q, andthe spring-pin H, arranged in a recess of the bed-plate, and extendinginto the slot q when the plate is in position, as set forth.

ln testimony whereof I have signed my name to this specification in thepresence of two subscribingwitnesses.

Witnesses:

WM. A. STEEL, J. SEERBORNE SINGER.

GEO. REHFUSS'.

